W.J. Conradie1, P.J. Raath1,2*, A.R. Mulidzi3 and C.L. Howell3
(1) Formerly ARC Infruitec-Nietvoorbij#, Private Bag X5026, 7599, Stellenbosch, South Africa.
(2) Department Horticultural Science, Stellenbosch University, Private Bag X1, 7602 Matieland, South Africa.
(3) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa.